For the
first time in more than two years, the astronauts aboard the International Space
Station (ISS) will step outside their spacecraft clad in U.S. spacesuits during
their mission's first spacewalk, NASA officials said Thursday.

ISS Expedition
12 commander Bill McArthur and flight engineer Valery Tokarev are scheduled
to exit the station at 9:30 a.m. EST (1430 GMT) on Nov. 7 for a 5.5-hour spacewalk
to revamp tools on the outpost's exterior.

"It's
pretty exciting," Tokarev told ABC News Wednesday of the spacewalk, which
will be a career for the Russian Federal Space Agency cosmonaut. "I've been
asking Bill a lot about his experience."

McArthur
has conducted two spacewalks - both during the shuttle Discovery's STS-92
mission to the ISS in 2000 - to support the station. He and Tokarev will leave
the ISS empty while they toil in space, leaving station control in the hands of
flight controllers on Earth.

"It is the
first time we've done a U.S. EVA without anyone inside," said Pete Hasbrook,
NASA's Expedition 12 increment manager, Thursday during a press conference at
the agency's Johnson Space Center in Houston, Texas. "We've been able to use a
lot of the lessons that we've learned from our preparations for the Russian
EVAs...[but] it certainly has not become routine for us."

The
spacewalk will also mark the first time since April 2003
that ISS astronauts left the station from its U.S.-built Quest airlock and worn
U.S. spacesuits. In the interim, ISS crews were limited
to two astronauts per flight after the Columbia accident and spacewalkers
relied on Russian-built Orlan
spacesuits for two-person EVAs.

Contamination
to both the airlock and the station's U.S. spacesuits - dubbed Extravehicular
Mobility Units (EMUs) by NASA - prevented the equipment from being used
earlier, though the portal has since been repaired and new spacesuits delivered
to the orbital platform.

Straightforward
tasks

McArthur
and Tokarev have two primary tasks to complete for their spacewalk, though
flight controllers do have some bonus chores waiting for them if there's time.

"The tasks
themselves are not overly challenging," explained Anna Jarvis, Expedition 12
EVA director, during the press conference. "We have not trained them in this
exact sequence, but they [require] very generic skills."

After
leaving the ISS airlock, McArthur and Tokarev will pull themselves
hand-over-hand to the leftmost edge of the space station - the tip of its P1
truss - to install a camera, lights and stand. The camera, which McArthur
said would weigh a couple of hundred pounds on Earth, will provide ISS views
during future station assembly spacewalks.

"As we say
on the farm, it would take two men and a boy to carry this around," McArthur
told CBS News Wednesday while Tokarev appeared to effortlessly tote the camera
equipment in microgravity.

The
Expedition 12 crew will then retrace their steps across about 60 feet (18 meters)
to the Quest airlock, retrieve tools then climb another 60 feet (18 meters) or
so the pinnacle of the space station - a solar array tower dubbed the P6
truss, Jarvis said.

Once there,
McArthur will remove a device called the Floating Potential Probe, which monitors
the electric potential of the station as it flies through Earth's magnetic
field, and cast it into space.

The probe
has failed and appears to be backing out of its berth in photographs, so
McArthur will jettison it aft and above the ISS to prevent it from breaking
free on its own, Hasbrook said, adding that the probe will burn up after 100
days or so.

If the
Expedition 12 crew has extra time after completing those tasks, they may also
retrieve a broken radiator rotary joint motor controller and replace a faulty
circuit breaker attached to station's railcar-like mobile transporter.

A
scientific beginning

After a
full month aboard the ISS - McArthur and Tokarev boarded
the orbital lab on Oct. 3 - the two astronauts are just beginning their
six-month science program.

In addition
to repairs and other science studies, McArthur has worked with the station's Human
Research Facility rack 2 (HRF-2) and performed the first of three kidney stone
experiment measurements alongside Tokarev. The kidney stone experiment studies
how spaceflight increases the risk of kidney stones, NASA's Expedition 12 lead
scientist Julie Robinson said.

More than
9,400 students on the Earth tapped into an Earth-watching camera - conveniently
named EarthKam
- to observe their home planet remotely, while meteorologists are using the
Expedition 12 crew's photographs of Hurricane Wilma to better understand the
massive storms, NASA officials said. Meanwhile McArthur awaits additional
science experiment equipment slated to launch toward the ISS aboard an unmanned
Russian cargo ship on Dec. 21, the added.

"We're
really just getting started on the research for this expedition," Robinson said.